ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Increasing demand factors in residential
by tortuga - 03/28/24 05:57 PM
Portable generator question
by Steve Miller - 03/19/24 08:50 PM
Do we need grounding?
by NORCAL - 03/19/24 05:11 PM
240V only in a home and NEC?
by dsk - 03/19/24 06:33 AM
Cordless Tools: The Obvious Question
by renosteinke - 03/14/24 08:05 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
0 members (), 265 guests, and 15 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
#187383 06/25/09 12:09 AM
Joined: Jul 2005
Posts: 183
J
jay8 Offline OP
Member
FYI,I just noticed Siemens has put out a two pole AFCI breaker, I am sure the other manufacturers will follow. It was the first I had heard of this.

jay8 #187452 06/27/09 02:04 AM
Joined: Nov 2005
Posts: 141
C
Member
Hey jay8, can you post a link or something??. I've been looking for about a hour now and don't see it.

Thanks.

Joined: Jul 2006
Posts: 27
C
Member

Last edited by canuck; 06/27/09 07:37 PM.
canuck #187472 06/27/09 07:56 PM
Joined: Jul 2006
Posts: 27
C
Member
Here's Schneider's info concerning shared neutrals and AFCI's:
http://ecatalog.squared.com/pubs/Ci...rrupters%20%28AFCI%29/0760DB0203R902.pdf
more at:
http://arcfault.ca

Joined: Jul 2005
Posts: 183
J
jay8 Offline OP
Member
sorry, forgot to include a link, thanks to canuck for taking care of business.

jay8 #187544 07/01/09 12:40 AM
Joined: Dec 2001
Posts: 444
S
Member
2 pole has been available for at least 2 years now in the Cutler Hammer line.


Sandro #187586 07/02/09 03:00 PM
Joined: Jun 2006
Posts: 613
M
Member
I am wondering what would require a 2 pole AFCI? I can't think of any branch circuit that requires it. Maybe the latest NEC has a few? Nothing mandatory in the CEC.
I am not saying there are no good or rational reasons for an AFCI 2 pole branch circuit just nothing in the code requiring one.

mikesh #187587 07/02/09 04:11 PM
Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
I am not aware of how the Canadian codes treat what we call "multi-wire branch circuits,' or, less formally, 'shared neutrals.'

This is the practice of running a three wire cable from the panel to the first junction box, where the two circuits are separated. Thus, they both use the same neutral for the final run back to the panel.

For such a circuit, the GFCI or AFCI breaker must, necessairily, control both of the 'hot' wires; thus the need for a two-pole breaker.

Here the more current issue relates to a design change in the AFCI's themselves .... no point opening that can of worms here!

It's also not unusual for the room air conditioner or baseboard heat to be a 240v circuit.

Last edited by renosteinke; 07/06/09 04:03 PM.
Joined: Jun 2006
Posts: 613
M
Member
Yes we do have multi wire branch circuits as you describe but if I was doing it I would not use a 2 pole breaker since the cost is more than double a 1 pole. For GFCI we generally install a GFCI outlet at the first outlet and seldom use a breaker. IE normal 1 pole breaker and GFCI outlet at the first required location. No common trip is required for a 3 wire circuit unless the devices are on the same mounting strap like as for split receptacles. It is possible to run 2 circuits from 2 X 1 pole CB on different buss with 1 neutral and a GFCI outlet at the first receptacle in each branch. Obviously the neutrals cannot share beyond this point or the service guy will slap someone on the back of the head ;-)
An AFCI circuit requires breaker protection as the entire branch must be AFCI protected. The only outlets required to be AFCI protected are the bedroom Plugs only. No smoke alarms may be on the circuit and lighting may be on the circuit. The cost of an AFCI 1 pole breaker was around CDN $70.00 and 2 pole around $250.00 even for a long home run it is still much cheaper to run 2 circuits.

mikesh #187662 07/06/09 04:17 PM
Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
Oh, I won't argue the economics one bit. Indeed, that's been at the heart of the AFCI debate here!

Originally, they were to allow AFCI devices, so you could handle things as you did with GFCI protection. When the requirement actually took efect (1999), though, the code was suddenly re-written to proscribe the devices. Later editions have made devices acceptable under certain restricted situations .... but the device makers have not made the devices available. Once bit, twice shy! For the guy in the field, it remains a puzzle how a 'protection' available in the device costs only $10 extra, while it costs at least $35 additional if the protection is placed in the breaker.

There are any number of reasons why MWBC's are used ... what is worth noting is that our most recent edition (2008) surprised us with numerous new restrictions upon their use. The next edition has several proposals to restrict them even further. Much to my surprise, one breaker manufacturer (Square D) is leading the charge, with a published opinion that MWBC's ought to be eliminated altogether. Personally, I cannot understand why Square D is concerned about this design issue.

Page 1 of 2 1 2

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5